Engine coolant flow controlling valve

ABSTRACT

An engine coolant flow controlling valve for governing the flow of engine coolant to a heater core comprises a valve housing defining first and second ports for respectively introducing coolant to the valve housing from the engine and directing coolant to the engine from the housing, said first and second ports opening into said housing adjacent each other in a housing wall, and third and fourth ports for respectively directing coolant from the housing to the heater core and introducing coolant from the heater core to the housing; a ceramic valving member supported for translational movement in the housing between a first position wherein coolant flows to said heater core via the first and third ports and returns to the engine via the second and fourth ports and a second position wherein the valving member blocks flow through the third and fourth ports and coolant flows from the first port to the second port bypassing said heater core. A valving member operator assembly extends into the housing for moving the valving member; and a valving member engaging assembly for resiliently maintaining the valving member in sealing engagement with the housing; the engaging assembly surrounding each of the third and fourth ports in sealing relationship with the housing and sealingly engaged with said valving member at least when the valving member is in its second position.

TECHNICAL FIELD

The present invention relates to valves for controlling engine coolantflow to heat exchangers in automotive vehicle heating systems and moreparticularly to coolant control valves constructed to bypass enginecoolant around the heat exchanger while controlling the flow.

BACKGROUND ART

Automotive vehicles driven by liquid cooled engines generally employ apassenger compartment heating system having a flow tube type heatexchanger (heater core) through which engine coolant flows. Air passingover the heater core is heated and directed into the passengercompartment to warm the compartment. The coolant flow rate through theheater core affects the amount of heat transferred into the passengercompartment. Coolant control valves have been employed for governing thecoolant flow through the heater cores to control passenger compartmenttemperatures.

Liguid cooled automotive vehicle engines generally employ a coolantcomposed of at least 50% ethylene glycol, or an equivalent compound, andwater. Ethylene glycol prevents the coolant from freezing in coldclimates, or seasons, and is usually thought of as an "antifreeze"additive; however, ethylene glycol is an extremely effective wettingagent. As such, ethylene glycol greatly increases the ability of enginecoolant to gain or lose heat while flowing through engine coolingpassages or heat exchanger tubes, even though the heat capacity ofethylene glycol is not as great as that of water. Thus the presence ofethylene glycol in engine cooling systems is desirable regardless ofambient atmospheric temperatures.

Engine coolant systems typically contain abrasive particulate matterwhich circulates with the coolant. The particulates, together withethylene glycol, tend to foul coolant flow control valves. Fouled valvescan stick, or jam, in a particular position and fail to control thecoolant flow in response to passenger compartment temperature. Thisnearly invariably results in vehicle occupant discomfort andnecessitates control valve repair or replacement.

Engine coolant flow control valves have been proposed in which variableproportions of the coolant flowing to the control valve bypasses theheater core. Examples of such valves are disclosed by U.S. Pat. Nos.3,477,498 and 4,195,777. Valves of the sort disclosed by these patentsare of relatively complex construction in that they contain manycomponent parts including multiple valving members and are not easilyassembled. Such valves can be relatively expensive to purchase,particularly as replacement parts, and are sometimes subject to beingfouled and rendered inoperative by materials in the engine coolantflowing through them. In addition the pressure drop of the coolantflowing through the valve can change substantially between the heatingcondition and the bypass condition.

DISCLOSURE OF THE INVENTION

The present invention provides a new and improved engine coolant flowcontrolling valve assembly wherein engine coolant is supplied to aheater core in accordance with positioning a coolant flow controllingvalving member between one position where flow to the heater core ismaximized and a second position wherein coolant flow bypasses the heatercore and communication with the heater core is blocked. The new flowcontrol valve is constructed of a relatively few, simple and easilyassembled elements, and resists sticking, jamming or other malfunctionsresulting from prolonged exposure to the engine coolant.

In a preferred embodiment the coolant control valve comprises a valvehousing, a ceramic valving member translatably movable in the housingbetween a first position wherein engine coolant flows through the heatexchanger and a second position wherein the valving member bypasses thecoolant from the heat exchanger and returns it to the engine, a valvingmember operator assembly, and a valving member engaging assembly forsealing the valving member. The valve housing defines first and secondports opening into a valving member slide surface by which coolant issupplied to and delivered from the engine, and third and fourth ports bywhich coolant is supplied to and delivered from the heat exchanger. Thevalving member provides a sealing land sealingly engaging the slidesurface and extending about a recessed face so that in the secondvalving member position the sealing land surrounds the first and secondports and coolant flows between the first and second ports via therecessed face. A valve port opens into the recessed face and is locatedto be aligned with the second and fourth ports when the valving memberis in its first position. The valving member engaging assembly sealinglysurrounds each of the third and fourth ports and seals against thevalving member so that when the valving member is in its secondposition, flow through the valve port and through the third and fourthports is blocked.

The preferred valving member engaging assembly comprises first andsecond pressure members respectively surrounding the third and fourthports and structure for biasing the pressure members against the valvingmember to urge the valving member into sealing engagement with the valveslide surface.

Other features and advantages of the invention will become apparent fromthe following detailed description of a preferred embodiment made withreference to the accompanying drawings which form a part of thespecification.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows part of a vehicle engine cooling system constructedaccording to the invention with portions schematically illustrated; and,

FIG. 2 is a cross-sectional view seen approximately from the planeindicated by the line 2--2 of FIG. 1.

DESCRIPTION OF A PREFERRED EMBODIMENT

Part of a vehicle engine coolant system 10 for heating a vehiclepassenger compartment is illustrated by FIG. 1 of the drawings. Thesystem 10 is associated with an engine 11 having an engine drivencoolant pump 11 for circulating coolant in the coolant system. Theillustrated passenger compartment heating system portion includes acoolant flow controlling valve assembly 12 and a heat exchanger 14,schematically illustrated. The heat exchanger 14 is preferably aconventionally constructed heater core of the type typically used inautomotive vehicles to heat air which is directed into the passengercompartment for heating the passenger compartment.

The valve assembly 12 is constructed and arranged to control the flowrate of engine coolant through the heater core 14 and thus control theamount of heat transferred into the passenger compartment of thevehicle. The valve assembly 12 is connected to the engine by coolantsupply and return lines 16, 18, respectively. The valve assembly 12 isoperated to provide a controlled flow of engine coolant to the heatercore 14 through a heater core supply line 20. The coolant passingthrough the heater core 14 is returned to the engine 11 by a heater corereturn line 22, the valve assembly 12 and the coolant return line 18.The lines 16, 18, 20 and 22 are preferably typical cloth reinforcedrubberized coolant hoses and are therefore shown schematically.

The valve assembly 12 comprises a valve housing assembly 30 definingfirst and second ports 32, 34 associated with the coolant supply andreturn lines 16, 18, respectively, and third and fourth ports 36, 38associated with the heater core supply and return lines 20, 22,respectively. The valve assembly 12 also includes a valving member 40disposed in the housing assembly 30, a valving member operatingmechanism 42 associated with the assembly 30 for actuating the valvingmember 40 between operative positions to control the coolant flowthrough the assembly 12, and a valving member engaging assembly 44coacting with the housing assembly 30 and the valving member 40.

The housing assembly 30 comprises molded housing members 50, 52 whichare bonded together to define an interior valving chamber 54. Thehousing members are preferably molded from a glass-filled polyamidthermoplastic material, but other materials can be used.

The housing member 50 is defined by a plate-like body 56 forming ahousing wall and a peripheral mounting flange 60 disposed about thehousing wall. The housing wall defines a planar valve slide surface 62along one side of the chamber 54. The first and second coolant ports 32,34 open into the chamber through the slide surface. The slide surface 62extends beyond the second port 34 to a well-like chamber section 54awhich, in the preferred orientation of the assembly 12, is at itslower-most end. Pipe-like coolant hose connectors 64, 66, moldedintegrally with the body 56, extend to the lines 16, 18 respectively.The hose connectors 64, 66 are supported with respect to each other andthe body 56 by reinforcing webs 68 which also extend to the mountingflange 60.

The housing member 52 forms a peripheral valve chamber wall 70 disposedabout the valve chamber 54 and a second wall construction 72 confrontingthe housing wall formed by the body 56. The wall construction 72 definesthe third and fourth ports 36, 38 which are aligned with the first andsecond ports 32, 34, respectively. The ports 36, 38 are constructed toprovide projecting external ends 74, 76 forming hose connections for thelines 20, 22, respectively. The housing member 52 further includesmolded-in mounting screw receiving bosses 78 and coacting structures onthe mounting flange 60 so that the assembly 12 can be suitably securedin place where desired in the vehicle for example, attached to bracketsadjacent the heater core structure itself.

The valving member 40 is a plate-like ceramic element translatablymovable in the chamber 54 to meter the coolant flowing through theheater core 14. The side of the valving member facing the slide surface62 forms a recessed face 82 completely surrounded by a peripheralsealing land 84 extending from the face 82 into sealing engagement withthe slide surface 62. A valve port 85 opens in the recessed face 82 andextends through the valving member. The opposite valving member sidedefines a smooth planar surface 88 engaged by the valving memberengaging assembly 44.

The valving member 40 is shaped and sized so that the land 44 extendsabout the first and second ports when positioned as illustrated by FIG.2. In this position of the valving member the coolant flow from theengine bypasses the heater core by flowing through a by-pass passagewayformed by the recessed valving member face 82. Thus coolant flowing tothe valve assembly 12 through the line 16 is returned to the enginethrough the line 18 without passing through the heater core 14. Thedistance the face 82 is recessed in the valving member to produce apressure drop in the bypassed coolant which is substantially the same asthat provided by the heater core 14.

When the valving member 40 is slid fully into the chamber well section54a, the sealing land section 84a at the upper valving member extremity(as shown by FIG. 2) moves across the first port 32 to entirely blockbypass coolant flow since the land 84 is sealed against the valve slideface 62 about the second port 34 and prevents direct communicationbetween the ports 32, 34. The valving member engages the peripheralhousing wall 70 at the end of the slide surface 62 to limit the valvingmember motion. In this position the first and third ports directlycommunicate with each other as do the second and fourth ports via thevalve port 85 thereby assuring full flow of coolant through the heatercore 14. When the valving member 40 is positioned between its extremesof movement, part of the coolant delivered to the valve assembly 12flows through the heater core while the remainder of the coolant supplyby-passes the heater core and is returned to the engine.

The valving member land section 84a is provided with an axiallyextending "T" slot 90 by which the valving member is connected to theoperating mechanism 42. The operating mechanism 42 extends into thehousing assembly 30 to the valving member 40 for pushing the valvingmember toward the housing chamber well section 54a to maximize enginecoolant flow to the heater core and pulling the valving member away fromthe chamber well section to prevent flow to the heater core.

The operating mechanism 42 is preferably a lever system having agenerally U-shaped sheet metal support base 100 attached by suitableconnectors 102 to the housing mounting flange 60; a sheet metal bellcrank member 104 pinned to projecting legs of the U-shaped support base100 for rotation about a pivot axis 105; and an actuating rod 106pivoted to the bell crank member 104 and connected to the valving member40.

The rod 106 extends into the chamber 54 through a sealing gland 108supported in a boss 110 integral with the housing member 52. Theprojecting end of the rod 106 is provided with a headed knob 112interfitting with the valving member T-slot 90 to facilitate easyassembly of the rod and valving member yet assure positive motion of thevalving member 40 by the rod 106.

The bell crank 104 has an arm portion 104a suitable for connection tothe output arm of a pneumatic actuator or a conventional cable-typeactuator to enable rotation of the bell crank 104 about the axis 105 andconsequent translational actuation of the valving member 40 by the rod106.

The valving member engaging assembly 44 biases the valving member 40into sealing engagement with the valve slide face 62 and seals betweenthe valving member and the third and fourth ports. The preferredassembly 44 comprises first and second independent bearing members 120,122 each having a generally annular body defining a respective sealingface 124, 126 engaging the valve member face 88. The seal faces 124, 126respectively surround the third and fourth ports. Each bearing member120, 122 coacts with a respective resilient sealing ring 134, 136disposed in a sealing ring retaining groove extending concentricallyaround the associated one of the third and fourth ports. The sealingrings 134, 136 are cylindrical and formed of rubber-like material. Whenthe bearing members are disposed in the housing in contact with thevalving member 40 the rings 134, 136 are axially compressed andoutwardly bowed to both seal against the ring grooves and the bearingmembers and to bias the bearing members against the valving member. Thehousing member 52 is constructed with shoulder-like guide surfacesradially adjacent each bearing member to maintain alignment of thebearing members and their respective ports and enable limited axialbearing member movement.

The bearing members 120, 122 are preferably formed from ceramic materiallike the valving member 40. The bearing members 120, 122 are shaped andsized so that when the valving member 40 is in the position illustratedby FIG. 2, the valve port 85 is disposed against the bearing membersealing faces 124, 126 and away from alignment with either the third orfourth port. Accordingly none of the coolant flowing through the bypasspassage formed by the recessed valving member face 82 can flow along thevalve face 88 to either the third or the fourth port. Thus the valvingmember 40 and the bearing members 120, 122 positively preventcommunication of the heater core 14 with the coolant delivered to thevalve assembly 12 in the by-passing mode of the valve assembly.

While a single embodiment of the present invention has been illustratedand described herein in considerable detail, the present invention isnot to be considered limited to the precise construction disclosed.Various adaptations, modifications and uses of the invention may occurto those skilled in the art to which the invention relates and theintention is to cover hereby all such adaptations, modifications anduses falling within the scope or spirit of the appended claims.

We claim:
 1. An engine coolant flow controlling valve for governing theflow of engine coolant to a heat exchanger comprising:(a) a valvehousing defining first and second ports for respectively introducingcoolant to the valve housing from the engine and directing coolant tothe engine from the housing, said first and second ports opening intosaid housing adjacent each other in a housing wall, and third and fourthports for respectively directing coolant from the housing to the heatexchanger and introducing coolant from the heat exchanger to thehousing; (b) a ceramic valving member supported for translationalmovement in said housing between a first position wherein coolant flowsto said heat exchanger via said first and third ports and returns to theengine via said second and fourth ports and a second position whereinsaid valving member blocks flow through said third and fourth ports sothat coolant flows from said first port to said second port bypassingsaid heat exchanger, said valving member having one side slidablyengaging a valving member slide surface formed on said housing wall insealing engagement therewith, said valving member movable along saidslide surface between said positions; (c) valving member operator meansextending into said housing for moving said valving member, and (d)valving member engaging means for resiliently maintaining said valvingmember in sealing engagement with said housing wall, said engaging meanssurrounding each of said third and fourth ports in sealing relationshipwith said housing and sealingly engaged with said valving member atleast when said valving member is in said second position; (e) saidvalving member defining a recessed area within said one lateral sidewith a valve port opening through said valving member into said recessedarea, said recessed area shaped to overlie said first and second portswhen said valving member is in said second position, said valving memberengaging means sealingly engaged with said valving member to preventflow through said valve port to said third and fourth ports.
 2. Thevalve claimed in claim 1 wherein said recessed area is surrounded by acontinuous sealing land extending into sealing engagement with saidvalve slide surface, said sealing land extending about said first andsecond ports when said valving member is in said second position.
 3. Thevalve claimed in claims 1 or 2 wherein said valving member engagingmeans comprises first and second pressure members respectivelysurrounding said third and fourth ports and biasing means for urging thepressure members towards engagement with the valving member, saidpressure members sealingly engaging said valving member in its secondposition to prevent communication between said valve port and said thirdand fourth ports.
 4. The valve claimed in claim 3 wherein said third andfourth ports are formed in a second housing wall opposite to saidvalving member slide surface, said slide surface having a valving memberengaging portion adjacent one of said first and second ports andextending therefrom in a direction away from the other of said first andsecond ports, said valving member overlying said slide surface portionand said one of said first and second ports with said valve portsubstantially aligned with said one port when said valving member is insaid first position.
 5. The valve claimed in claim 1 wherein saidhousing is formed by first and second housing members attached togetherto form a chamber for said valving member, one of said housing membersdefining an integral outwardly extending mounting flange, said operatormeans comprising a support member fixed to said flange, a crank pivotedto said support member and an actuating rod connected to said crank andextending into said chamber, said rod connected to said valving member.